lkml.org 
[lkml]   [2011]   [Dec]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH] mm: mmap system call does not return EOVERFLOW
    > To fix this bug, it is necessary to compare "off" plus "len"
    > with "off" by units of "off_t". The patch is here:
    >
    > Signed-off-by: Naotaka Hamaguchi <n.hamaguchi@jp.fujitsu.com>
    > ---
    >  mm/mmap.c |    3 ++-
    >  1 files changed, 2 insertions(+), 1 deletions(-)
    >
    > diff --git a/mm/mmap.c b/mm/mmap.c
    > index eae90af..e74e736 100644
    > --- a/mm/mmap.c
    > +++ b/mm/mmap.c
    > @@ -948,6 +948,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
    >        vm_flags_t vm_flags;
    >        int error;
    >        unsigned long reqprot = prot;
    > +       off_t off = pgoff << PAGE_SHIFT;
    >
    >        /*
    >         * Does the application expect PROT_READ to imply PROT_EXEC?
    > @@ -971,7 +972,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
    >                return -ENOMEM;
    >
    >        /* offset overflow? */
    > -       if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
    > +       if ((off + len) < off)
    >                return -EOVERFLOW;

    Hmm...
    pgoff doesn't make actual overflow. do_mmap_pgoff() can calculate big
    value. We have
    no reason to make artificial limit. Why don't you meke a overflow
    check in sys_mmap()?
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2011-12-22 18:01    [W:3.479 / U:0.196 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site